You could say that the presidential campaign got a jolt of energy this week. President Obama was in Iowa yesterday, touting the electric potential of wind power. Republican rival Mitt Romney was in Ohio, talking up that old standby, coal. Each man accused the other of standing in the way of a rival energy source.

NPR's Scott Horsley has more.

SCOTT HORSLEY, BYLINE: There's a new crop sprouting up in the middle of Iowa's corn fields: giant windmills. President Obama, who's in the midst of a three-day bus tour across Iowa, stopped by the Laurel Wind Farm yesterday to take a look.

PRESIDENT BARACK OBAMA: The Heil family has been farming this land since 1902. But they've got a relatively new addition in the wind turbines that you see in the background.

HORSLEY: The wind farm includes 52 turbines, or windmills, which together produce enough power for 30,000 homes.

OBAMA: And I'm proud of the fact that while we used to have to import parts like those, today they're made in Newton.

HORSLEY: Newton, Iowa used to be known as the nation's washing machine capital, until the Maytag plant there shut down in 2007, in the midst of the last presidential campaign.

Part of that Maytag factory is now occupied by a windmill tower company. Statewide, the wind industry employs more than 6,000 people in Iowa.

Mr. Obama warns some of those jobs could be in jeopardy if a wind energy tax credit is allowed to expire this year, as Mitt Romney has proposed. The president accuses Romney of belittling wind power's potential.

OBAMA: During a speech a few months ago, Governor Romney explained his energy policy this way: You can't drive a car with a windmill on it. That's what he said about wind power. Now, I know he's tried some other things on top of a car. I didn't know he had tried windmills on top of a car.

(LAUGHTER)

HORSLEY: Across the country, wind power supplies just three percent of electricity. But here in Iowa that figures more like 20 percent. And Mr. Obama notes the nation's wind generating capacity has doubled in the last four years.

OBAMA: Coal is still by far the dominant fuel for making electricity, though its share dropped to about 42 percent last year. The combination of environmental regulations and cheap natural gas have discouraged development of new coal-fired power plants.

HORSLEY: Yesterday, Romney said that's a mistake.

MITT ROMNEY: We have 250 years of coal. Why in the heck wouldn't we use it?

HORSLEY: Romney was speaking at a Beallsville, Ohio coal mine owned by Murray Energy, a company with a history of flouting government regulations. A Murray subsidiary was fined half-a-million dollars after the deadly 2007 collapse of a Utah mine that killed nine people.

CEO Bob Murray blames regulatory moves by the Obama administration for the closure of an Ohio mine this year - a criticism that Romney picked up yesterday.

ROMNEY: You've probably heard the president say he's for all of the above. And I wondered what he meant, because I see how he's been waging war on coal. And I wondered, how could he possibly say that? Then it came to me. He's for all the sources of energy that come from above the ground, none of those that come from below the ground like oil and coal and gas.

HORSLEY: The Obama campaign disputes that, noting that coal mining employment hit a 15 year high last year. This might seem like a parochial contest involving two Midwestern swing states, windy Iowa and coal-rich Ohio, both trying to protect important local industries.

Iowa windmill makers want to maintain their government tax break, while Ohio coalminers want to beat back government regulation.

Romney couches this as a choice between the free market and government interference. Mr. Obama paints the choice differently.

OBAMA: We can listen to folks who want to take us backwards by doubling down on the same economic policies that got us into a fix several years ago and that we're still fighting out of, or we can keep moving forward to a future with more good American jobs, more sources of home-grown American energy, greater energy independence, and cleaner, safer environments for our kids.

HORSLEY: That's a popular position - at least here in Iowa - where one turbine developer described Romney's team yesterday as running against the wind.